XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 441
Installation of the CB Omni analyzer was achieved
within a 2-day scheduled shut. A belt scale was also
installed, as this is needed to provide throughput and
belt speed inputs to the analyzer, which are used to pro-
vide a kg/m input. The commissioning of the analyzer in
February 2023 required the conveyor belt to be isolated to
enable the reference standards to be measured at different
mass loadings in order to validate the factory calibration
and ensure the analyzer was ready to deliver accurate analy-
sis of primary crusher product material. These belt isola-
tions were done over two separate days to maintain feed to
the stockpile but could be achieved in a single 2-day period
if stockpile reserves were sufficient to maintain mill opera-
tion. Figure 3 shows the CB Omni analyzer installed on the
conveyor, situated between the primary crusher and coarse
ore stockpile.
A key benefit in the factory calibration process
employed by Thermo Fisher Scientific is that minimal on-
site calibration effort is required. Previous experience with
other PGNAA analyzers, (e.g., Scott 2020), has indicated
a requirement for significant sampling of analyzed feed for
dynamic calibration, as well as a strong correlation between
analyzed mass and reported grade in the absence of dynamic
calibration. The comprehensive calibration process used by
Thermo Fisher Scientific ensures accuracy independent of
analyzed mass, as shown in Figure 4, which shows there is
no correlation between dynamic analysis results and tons
per hour.
Once the factory calibration has been validated, the
customer can expect the analyzer to be producing accu-
rate and reliable results. This approach delivers trustworthy
analysis over a wider range of material in the initial phase
of an optimization project encouraging earlier adoption of
sensor data for process improvements. Delays in adoption
of results and costly belt stops to acquire validation samples
are eliminated with obvious follow-on cost savings and
accelerating return on investment.
Naturally, to gain confidence in the analyzer results,
a comparison with independent plant data is desirable.
Sampling conveyed flows without an automatic sampler
is challenging and potentially unreliable due to sampling
errors. Another approach is to use existing upstream and
downstream data sources, with careful accounting for time
differences between the CB Omni measurements and avail-
able assay information. This approach was taken during
the 6-month trial to validate that the CB Omni analysis
was in line with typical existing plant data, namely Grade
Control assays from blast hole samples and On-Stream
XRF Analysis of cyclone overflow after the mill. Figure 5
shows the %Cu comparison between the upstream Grade
Control, CB Omni and downstream OSA. The %Cu val-
ues have been normalized over a 0–1 range, rather than pre-
senting the actual grade.
At Red Chris, grade control assays are derived from
analysis of blast hole drill cuttings samples. Blast holes are
13m deep × 30cm diameter for each 10 × 10 × 12meter
Figure 1. Copper and sulfur factory calibration results for reference standards and customer samples
Installation of the CB Omni analyzer was achieved
within a 2-day scheduled shut. A belt scale was also
installed, as this is needed to provide throughput and
belt speed inputs to the analyzer, which are used to pro-
vide a kg/m input. The commissioning of the analyzer in
February 2023 required the conveyor belt to be isolated to
enable the reference standards to be measured at different
mass loadings in order to validate the factory calibration
and ensure the analyzer was ready to deliver accurate analy-
sis of primary crusher product material. These belt isola-
tions were done over two separate days to maintain feed to
the stockpile but could be achieved in a single 2-day period
if stockpile reserves were sufficient to maintain mill opera-
tion. Figure 3 shows the CB Omni analyzer installed on the
conveyor, situated between the primary crusher and coarse
ore stockpile.
A key benefit in the factory calibration process
employed by Thermo Fisher Scientific is that minimal on-
site calibration effort is required. Previous experience with
other PGNAA analyzers, (e.g., Scott 2020), has indicated
a requirement for significant sampling of analyzed feed for
dynamic calibration, as well as a strong correlation between
analyzed mass and reported grade in the absence of dynamic
calibration. The comprehensive calibration process used by
Thermo Fisher Scientific ensures accuracy independent of
analyzed mass, as shown in Figure 4, which shows there is
no correlation between dynamic analysis results and tons
per hour.
Once the factory calibration has been validated, the
customer can expect the analyzer to be producing accu-
rate and reliable results. This approach delivers trustworthy
analysis over a wider range of material in the initial phase
of an optimization project encouraging earlier adoption of
sensor data for process improvements. Delays in adoption
of results and costly belt stops to acquire validation samples
are eliminated with obvious follow-on cost savings and
accelerating return on investment.
Naturally, to gain confidence in the analyzer results,
a comparison with independent plant data is desirable.
Sampling conveyed flows without an automatic sampler
is challenging and potentially unreliable due to sampling
errors. Another approach is to use existing upstream and
downstream data sources, with careful accounting for time
differences between the CB Omni measurements and avail-
able assay information. This approach was taken during
the 6-month trial to validate that the CB Omni analysis
was in line with typical existing plant data, namely Grade
Control assays from blast hole samples and On-Stream
XRF Analysis of cyclone overflow after the mill. Figure 5
shows the %Cu comparison between the upstream Grade
Control, CB Omni and downstream OSA. The %Cu val-
ues have been normalized over a 0–1 range, rather than pre-
senting the actual grade.
At Red Chris, grade control assays are derived from
analysis of blast hole drill cuttings samples. Blast holes are
13m deep × 30cm diameter for each 10 × 10 × 12meter
Figure 1. Copper and sulfur factory calibration results for reference standards and customer samples